docs: def get_keygrip(user_id, sp=subprocess):
      """Get a keygrip of the primary GPG key of the specified user."""
      args = gpg_command(['--list-keys', '--with-keygrip', user_id])
      output = check_output(args=args, sp=sp).decode('utf-8')
      return re.findall(r'Keygrip = (\w+)', output)[0]